CN116819801A

CN116819801A - Control method, device and system of polarization controller and storage medium

Info

Publication number: CN116819801A
Application number: CN202210288181.7A
Authority: CN
Inventors: 张森; 范林生
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-03-22
Filing date: 2022-03-22
Publication date: 2023-09-29

Abstract

The application discloses a control method, a device, a system and a storage medium of a polarization controller, and belongs to the technical field of optical communication. The method comprises the following steps: if the sum of the current value of the control parameter of the first optical phase shifting component and the initial adjustment quantity exceeds a first boundary of a first allowable value interval, adjusting the value of the control parameter of the first optical phase shifting component and the second optical phase shifting component so that the value of the control parameter of the first optical phase shifting component is positioned in the first allowable value interval and the absolute value of the difference value between the control parameter of the first optical phase shifting component and the first boundary exceeds the absolute value of the initial adjustment quantity, and the polarization state of the optical signal after adjustment passing through the polarization controller is the same as the polarization state corresponding to the initial adjustment quantity, or the polarization state of the optical signal before and after adjustment passing through the polarization controller is unchanged. The polarization state of the optical signal is unchanged or reaches the original expected polarization state before and after resetting while resetting the optical phase shifting assembly, so that service data is not required to be interrupted in the resetting process, and the service data transmission efficiency is improved.

Description

Control method, device and system of polarization controller and storage medium

Technical Field

The present application relates to the field of optical communications technologies, and in particular, to a method, an apparatus, a system, and a storage medium for controlling a polarization controller.

Background

In an optical communication network, service data is modulated into an optical signal, and transmission of the service data is realized through transmission of the optical signal. However, during the transmission of the optical signal, the polarization state of the optical signal is easily affected by the environment to rotate, and in a polarization sensitive scene, the polarization state of the optical signal is usually required to be the target polarization state, so that the receiver can correctly demodulate the service data in the optical signal. Based on this, a polarization controller capable of rotating the polarization state of an optical signal to a target polarization state is widely used.

In general, the polarization state of the optical signal may vary with the phase difference between the horizontal polarization state component and the vertical polarization state component, so in the case that the polarization controller includes a plurality of optical phase shifters connected in series, each optical phase shifter may control the amount of phase shift between the horizontal polarization state component and the vertical polarization state component by adjusting the value of its own control voltage, and thus adjust the polarization state of the optical signal so that the polarization state of the optical signal reaches the target polarization state. However, in the process of adjusting the value of the control voltage of the optical phase shifter, when the value of the control voltage reaches the boundary of the allowed value interval, the control voltage needs to be reset so that the value of the control voltage can be continuously adjusted later. In the process of resetting the control voltage, the polarization state of the optical signal can be suddenly changed, so that the polarization state of the optical signal is unstable, and further, the situation of error of service data transmission occurs. In order to avoid this, the transmitter is controlled to suspend the modulation of the service data into the optical signal, i.e. to suspend the transmission of the service data, before the control voltage is reset, so that the optical signal input to the polarization controller is an invalid optical signal during the process of resetting the control voltage, and accordingly, the influence of the resetting process on the transmission of the service data is avoided.

In the process of resetting the control voltage, the service data in the optical communication network can be paused to be sent. If the polarization state of the optical signal input to the polarization controller changes rapidly, which means that the polarization controller needs to be reset frequently, the service data transmission efficiency is seriously affected in the above manner.

Disclosure of Invention

The application provides a control method, a device, a system and a storage medium of a polarization controller, which can not interrupt service data in the process of resetting an optical phase shifter, thereby improving the transmission efficiency of the service data. The technical scheme is as follows:

in a first aspect, a method for controlling a polarization controller is provided. The polarization controller comprises N optical phase shifting components, wherein N is a positive integer greater than 1. In the method, an initial adjustment amount of a control parameter of a first optical phase shift assembly for controlling a phase shift amount of an optical signal passing through a corresponding optical phase shift assembly, the phase shift amount being a phase difference between a horizontal polarization state component and a vertical polarization state component of the optical signal, is determined based on a target polarization state of the optical signal output from a polarization controller.

If the sum of the current value of the control parameter of the first optical phase shifting component and the initial adjustment quantity exceeds a first boundary of a first allowable value interval, adjusting the value of the control parameter of the first optical phase shifting component and the second optical phase shifting component so that the value of the control parameter of the first optical phase shifting component is positioned in the first allowable value interval and the absolute value of the difference value between the control parameter of the first optical phase shifting component and the first boundary exceeds the absolute value of the initial adjustment quantity, and the polarization state of the optical signal after adjustment passing through the polarization controller is the same as the polarization state corresponding to the initial adjustment quantity, or the polarization state of the optical signal before and after adjustment passing through the polarization controller is unchanged. The second optical phase shifting component is an optical phase shifting component except the first optical phase shifting component in the N optical phase shifting components.

The polarization state corresponding to the initial adjustment can be understood as: the control parameters of the first optical phase shifting element are assumed to be adjusted according to the initial adjustment amount, and the assumption is that the polarization state of the optical signal output by the polarization controller in the scene, that is, the polarization state originally expected to be achieved by the initial adjustment amount, may be simply referred to as the original expected polarization state in the following.

The application can realize the following technical effects:

(1) Resetting control parameters of optical phase shifting assembly with control parameters reaching boundary quickly

If the sum of the current value of the control parameter of the first optical phase shifting component and the initial adjustment quantity exceeds the first boundary of the first allowable value interval, the current value of the control parameter of the first optical phase shifting component is indicated to be close to the first boundary, and the value of the control parameter of the first optical phase shifting component needs to be reset at the moment, so that the control parameter of the first optical phase shifting component can be adjusted continuously based on the reset value. In the embodiment of the application, the control parameter of the first optical phase shift assembly is reset, namely the value of the control parameter of the first optical phase shift is adjusted, so that the adjusted value is far away from the first boundary, and the subsequent continuous adjustment based on the adjusted value is facilitated.

The value of the control parameter of the first optical phase shifting component after adjustment is positioned in the first allowable value interval, and the absolute value of the difference value between the first optical phase shifting component and the first boundary exceeds the absolute value of the initial adjustment quantity, so that the value of the control parameter of the first optical phase shifting component after adjustment can meet the condition required by the next adjustment. That is, the adjustment of the control parameter of the first optical phase shift assembly in the application can realize the reset of the control parameter of the first optical phase shift assembly.

(2) The polarization state of the output optical signal is ensured to be unchanged or reach the original expected polarization state in the resetting process.

Based on the above two technical effects, in the present application, by adjusting the control parameters of the first optical phase shift assembly and the second optical phase shift assembly at the same time, on the one hand, the resetting of the control parameters of the first optical phase shift assembly can be completed. On the other hand, the specific adjustment content of the control parameters of the first optical phase shifting component and the second optical phase shifting component is controlled to realize that the polarization state of the first optical signal is unchanged or reaches the original expected polarization state before and after adjustment, so that the abrupt change of the polarization state of the optical signal in the resetting process is avoided. Because the polarization state of the optical signal is not suddenly changed in the process of resetting the control parameters of the optical phase shifting assembly, the transmission of service data is not required to be interrupted when the control parameters of the optical phase shifting assembly are reset through the control method, and accordingly the transmission efficiency of the service data can be improved.

In one possible implementation manner, the polarization controller further includes 4 couplers, N optical phase shifting components are connected in series, one coupler is connected between each adjacent two of the N-2 th to N-th optical phase shifting components, an input end of the N-2 nd optical phase shifting component is connected with one coupler, an output end of the N-th optical phase shifting component is connected with one coupler, and the coupler connected with the output end of the N-th optical phase shifting component is used for outputting the optical signal rotated by the polarization controller. In this case, the first optical phase shift element is one of the N-2 th to N-th optical phase shift elements, and the second optical phase shift element is one of the N-2 th to N-th optical phase shift elements other than the first optical phase shift element.

In the polarization controller, the optical signal in any polarization state can be rotated to the target polarization state through the adjustment of the control parameters of the last three-stage optical phase shifting assembly connected in series in the polarization controller, so that the control flow of the polarization controller is simplified.

In one possible implementation, the first optical phase shifting element is an nth order optical phase shifting element and the second optical phase shifting element is an N-1 th order optical phase shifting element. In this case, the process of adjusting the values of the control parameters of the first optical phase shifting element and the second optical phase shifting element may be: adjusting the value of a control parameter of the N-1 level optical phase shifting component according to a first step length, wherein the phase shifting variable quantity corresponding to the first step length is kpi/2, and k is an odd number; and adjusting the value of the control parameter of the Nth-stage optical phase shifting component according to the target adjustment quantity, wherein the absolute value of the target adjustment quantity is the same as that of the initial adjustment quantity, and the direction of the target adjustment quantity is opposite to that of the initial adjustment quantity. The polarization state of the optical signal after adjustment passing through the polarization controller is the same as the polarization state corresponding to the initial adjustment amount.

By the adjustment mode, the polarization state of the optical signal which is adjusted and passes through the polarization controller can be identical to the polarization state corresponding to the initial adjustment amount. That is, the control parameters of the first optical phase shifting component are reset, and meanwhile, the polarization state of the optical signal can be maintained to be the original expected polarization state, so that abrupt changes of the polarization state of the optical signal in the resetting process are avoided.

In one possible implementation, the first optical phase shifting component is an N-1 th order optical phase shifting component, and the second optical phase shifting component includes an N-2 th order optical phase shifting component and an N-2 th order optical phase shifting component. In this case, the implementation process of adjusting the values of the control parameters of the first optical phase shift assembly and the second optical phase shift assembly may be: adjusting the control parameter of the N-level optical phase shifting assembly from a first value to a second value, and adjusting the control parameter of the N-2-level optical phase shifting assembly from a third value to a fourth value, wherein the difference between the phase shift amount corresponding to the first value and the phase shift amount corresponding to the second value is the same as the difference between the phase shift amount corresponding to the third value and the phase shift amount corresponding to the fourth value; and adjusting the value of the control parameter of the N-1 level optical phase shifting component to a target value, wherein the target value is a numerical value in a target interval, the target interval is positioned in the range of the first allowable value interval, and the absolute value of the difference value between any numerical value in the target interval and the first boundary exceeds the absolute value of the initial adjustment quantity. Wherein, the polarization state of the optical signal passing through the polarization controller before and after the adjustment is unchanged.

By the adjustment mode, the polarization state of the optical signal which passes through the polarization controller after adjustment is strictly unchanged. That is, the polarization state of the optical signal can be kept strictly unchanged while the control parameter of the first optical phase shifting component is reset, so that abrupt change of the polarization state of the optical signal in the resetting process is avoided.

In one possible implementation, the phase shift amount corresponding to the second value is jpi, where j is an integer.

In the adjustment mode, the phase shift amount corresponding to the second value of the Nth optical shift component is j pi, and j is an integer, and because j is any integer, the value of the adjusted Nth optical shift component can be controlled to be not beyond the corresponding allowable value interval by controlling the value of j, so that the value of the adjusted Nth optical shift component is prevented from exceeding the corresponding allowable value interval.

In one possible implementation, the absolute value of the difference between any one of the values in the target interval and the second boundary exceeds the absolute value of the initial adjustment amount, and the second boundary is another boundary in the first allowable value interval other than the first boundary.

Further, in order to avoid that the control parameter of the N-1-th optical phase shift element is close to the second boundary of the first allowable value interval when the control parameter of the N-1-th optical phase shift element is adjusted next time, the control parameter of the N-1-th optical phase shift element is further away from the second boundary as far as possible when the control parameter of the N-1-th optical phase shift element is adjusted to any value away from the first boundary.

In one possible implementation manner, the adjusted value of the control parameter of the second optical phase shift component is located in a second allowable value interval, where the second allowable value interval is an allowable value interval corresponding to the control parameter of the second optical phase shift component.

In the process of simultaneously adjusting the control parameters of the first optical phase shifting component and the second optical phase shifting component, the control parameters of the second optical phase shifting component are prevented from being adjusted to the boundary as much as possible, and the second optical phase shifting component is required to be reset after initiation.

In one possible implementation, the first optical phase shifting component is an N-1 th order optical phase shifting component or an N-th order optical phase shifting component. In this case, the implementation process of determining the initial adjustment amount of the control parameter of the first optical phase shift assembly based on the target polarization state of the optical signal may be: acquiring Stokes vectors of optical signals output by an N-1-th stage coupler, wherein the N-1-th stage coupler is a coupler connected with the input end of an N-1-th stage optical phase shifting component; an initial adjustment of a control parameter of the first optical phase shifting component is determined based on the stokes vector and the target polarization state.

In one possible implementation, the polarization controller further comprises a polarization measuring instrument connected to the input of the N-1 stage optical phase shifting assembly. The polarization measuring instrument is used for detecting Stokes vectors.

The adjustment quantity required for adjusting the optical signal into the target polarization state can be directly obtained through the Stokes vector, the operation steps are few, and the control efficiency is high.

In one possible implementation, the process of determining the initial adjustment amount of the control parameter of the first optical phase shifting component based on the target polarization state of the optical signal may be: when the target polarization state is the horizontal polarization state, acquiring the power of a vertical optical signal in the optical signals output by the polarization controller, wherein the vertical optical signal refers to a vertical polarization state component in the optical signals input to the polarization controller; if the power exceeds the power threshold, an initial adjustment amount is determined based on the first allowable value interval and the second step size.

In one possible implementation, the polarization controller further includes a photodetector connected to a port in the polarization controller for outputting the optical signal; the photoelectric detector is used for detecting the power of the vertical optical signal in the optical signals output by the polarization controller.

The application can also adjust the control parameters of the controller step by step based on the self-adaptive control algorithm, and has higher control precision.

In a second aspect, there is provided a control device of a polarization controller, the device having a function of implementing the control method behavior of the polarization controller in the first aspect. The apparatus comprises at least one module for implementing the control method of the polarization controller provided in the first aspect.

In a third aspect, a control system is provided, where the control system includes a processor and a memory, where the memory is configured to store a program for supporting a control device to execute the control method provided in the first aspect, and store data related to implementing the control method in the first aspect. The processor is configured to execute a program stored in the memory. The control system may further comprise a communication bus for establishing a connection between the processor and the memory.

In a fourth aspect, there is provided a computer-readable storage medium having instructions stored therein, which when run on a computer, cause the computer to perform the method of controlling a polarization controller according to the first aspect described above.

In a fifth aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of controlling a polarization controller according to the first aspect described above.

The technical effects obtained by the second, third, fourth and fifth aspects are similar to the technical effects obtained by the corresponding technical means in the first aspect, and are not described in detail herein.

Drawings

FIG. 1 is a schematic diagram of a polarization controller according to an embodiment of the present application;

fig. 2 is a schematic diagram of a system architecture of an optical communication network according to an embodiment of the present application;

FIG. 3 is a flowchart of a control method of a polarization controller according to an embodiment of the present application;

FIG. 4 is a schematic diagram of another polarization controller according to an embodiment of the present application;

FIG. 5 is a schematic diagram of another method for controlling a polarization controller according to an embodiment of the present application;

FIG. 6 is a schematic diagram of another polarization controller according to an embodiment of the present application;

FIG. 7 is a schematic diagram of another method for controlling a polarization controller according to an embodiment of the present application;

FIG. 8 is a schematic diagram of another polarization controller according to an embodiment of the present application;

FIG. 9 is a schematic diagram of a control device of a polarization controller according to an embodiment of the present application;

Fig. 10 is a schematic structural diagram of a control system according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Before explaining the embodiment of the present application in detail, an application scenario of the embodiment of the present application is explained.

Optical communication technology is very widely used in large bandwidth, long-range communication systems. The processing of optical signals in optical communication technology is completed by various photoelectric chips. For example, the optical switch array chip may implement scheduling of optical wavelength or path, and the optical receiver chip may implement converting an optical signal into an electrical signal.

In addition, in order to further improve the integration level of the optoelectronic chip, silicon-based optical waveguide devices with high refractive index contrast are widely used in optical communication technology.

The silicon material is the basic material for manufacturing the integrated circuit, and the processing technology of the silicon-based optical waveguide device is compatible with the complementary metal oxide semiconductor (complementary metal oxide semiconductor, CMOS) technology, so that the silicon-based optical waveguide device can be manufactured at low cost, thereby having large-scale mass capacity. Silicon-based optical waveguide devices are sensitive to the polarization state of incident light and typically support transverse electric (transverse electric, TE) (i.e., horizontally polarized) transmission. Therefore, for the optical signal with random polarization state transmitted through the optical fiber, the polarization state of the optical signal needs to be controlled by a polarization controller (polarization controller, PC) before being coupled into the silicon-based optical waveguide device, so that the optical signal can be efficiently transmitted in the silicon-based optical waveguide device.

In addition, polarization multiplexing (polarization division multiplex, PDM) technology is becoming mature, and the principle of PDM is: in the same wavelength channel, two paths of independent data are transmitted simultaneously through two optical signals with mutually orthogonal polarization states, so that the purposes of doubling the total capacity of the system and the spectrum utilization rate are achieved. And the PDM technology can be combined with a novel modulation technology, a coherent detection technology and the like to further improve the system capacity. In the polarization multiplexing system based on the PDM technology, the receiving end can normally receive and demodulate the optical signals under the condition that the polarization states of the two paths of optical signals received by the receiving end are completely aligned with the polarization states of the two paths of optical signals transmitted by the transmitting end.

However, due to the fact that the factors such as asymmetry of circles, internal stress, pressure, bending and environmental temperature change in the use process of the optical fiber in the optical fiber production process can cause a double refraction effect in the optical fiber for transmitting the optical signals, the polarization state of the optical signals, which are transmitted by the transmitting end and are in the fixed polarization state, of the optical signals output after the optical signals are transmitted through the optical fiber is randomly rotated. Therefore, in the polarization multiplexing system, the polarization state of the optical signal sent by the sending end needs to be controlled by the polarization controller after the optical signal is transmitted by the optical fiber, so that the polarization states of the two paths of optical signals received by the receiving end and the polarization states of the two paths of optical signals sent by the sending end are completely aligned.

The polarization controller uses an electrical signal to drive the polarization state of the optical signal to rotate, and the electrical signal can be a control voltage or a control current, so that the range of the electrical signal applied to the polarization controller is limited due to the limitation of the hardware of the polarization controller. While the optical signal coupled to the polarization controller is arbitrarily transformed, so that there is a scene where the electrical signal needs to be reset when it reaches the positive/negative boundary. The polarization state of the optical signal output by the polarization controller is instantaneously changed in a resetting process, so that the polarization state of the optical signal output by the polarization controller is unstable, and therefore the polarization controller needs to solve the problem of electrodeless control, namely, the polarization state of the optical signal output in the resetting process is always kept stable.

The method provided by the embodiment of the application is applied to a scene capable of realizing electrodeless control in the control process of the polarization controller. The aim is to provide a method for realizing electrodeless control without interrupting effective data transmission.

For convenience of description, the following description of the polarization state of the optical signal is explained.

The polarization state of monochromatic fully polarized light can be represented by two orthogonal components perpendicular to the propagation direction, a horizontal polarization state component and a vertical polarization state component, respectively, with a phase difference between the two components. Writing two components in a column matrix form may represent The matrix form is Jones vector. For example, the Jones vector of horizontally linearly polarized light is +.>

The effect of polarization rotation (rotation of the state of polarization, RSOP) of an optical signal in an optical fiber link can be seen in jones space as the effect of a 2 x 2 jones matrix whose format is unitary. Wherein the unitary matrix has the following format:

wherein the parameters in equation (1) satisfy: u1. | ² +|U2| ² ＝1

Thus, the jones matrix corresponding to the polarization rotation of an optical signal in an optical fiber link can be expressed as:

wherein the parameters theta, delta and beta are randomly changed, and the RSOP effect in the optical fiber link can lead the polarization state of the input optical signal with horizontal polarization state to be random after the optical fiber is transmitted. Performing a mathematical transformation on the formula (2) to make

I.e. theEquation (2) can be expanded into a deflection rotation matrix as follows:

based on this, the polarization rotation process corresponding to the RSOP effect in the fiber link can be understood as: from an input optical signal, e.g. a linearly polarised lightAnd the optical signal obtained by multiplying the polarization rotation matrix is the optical signal output after being transmitted through the optical fiber link.

It should be noted that the jones vector describing the polarization state of an optical signal needs to be determined based on the amplitude and phase of the optical signal, and that it is difficult to directly measure the phase of the optical signal (unless by interference with another beam of known phase light). Thus, a method of measuring the polarization state based on the light intensity, which is also called a stokes vector method, has been developed. That is, the polarization state of the optical signal is described by a stokes vector.

The stokes vector has the following expression:

wherein S0, S1, S2 and S3 are light intensities of the light signals in three specified directions. After obtaining the stokes vector of the optical signal, the stokes vector can be used to derive the formula (5)And theta ₀ Parameters to facilitate other applications.

The hardware architecture and the network system according to the embodiments of the present application are explained below.

Fig. 1 is a schematic structural diagram of a polarization controller according to an embodiment of the present application. As shown in fig. 1, the polarization controller 100 includes a polarization beam splitter rotator (polarization splitter and rotator, PSR) 101, N optical phase shifting components 102, and n+1 couplers 103.N is a positive integer greater than 1.

Wherein N optical phase shifting elements 102 are connected in series. For convenience of explanation, as shown in fig. 1, N optical phase shift modules 102 connected in series in this order are referred to as first-stage optical phase shift modules 102, …, N-2-th-stage optical phase shift module 102, N-1-th-stage optical phase shift module 102, and N-th-stage optical phase shift module 102 in this order from the near to far distance from polarization beam splitter rotator 101. A coupler 103 is connected between the polarization beam splitting rotator 101 and the first-stage optical phase shifting component 102, a coupler 103 is connected between every two adjacent optical phase shifting components 102, and an output end of the Nth-stage optical phase shifting component 103 is connected with a coupler 102.

Further, n+1 couplers 103 from left to right in fig. 1 are sequentially referred to as first stage couplers 103, …, N-2 stage coupler 103, N-1 stage coupler 103, N stage coupler 103, and n+1 stage coupler 103. In this scenario, the connection relationship of the respective devices shown in fig. 1 can be understood as: the input end of the polarization beam splitting rotator 101 is used for inputting an optical signal to be processed, the two output ends of the polarization beam splitting rotator 101 are connected with the two input ends of the first-stage coupler 103, the two output ends of the first-stage coupler 103 are respectively connected with the two input ends of the first-stage optical phase shifting component 102, and so on, the two output ends of the nth-stage optical phase shifting component 102 are connected with the two input ends of the n+1th-stage coupler 103, and the two output ends of the n+1th-stage coupler 103 are used for outputting the optical signal after final processing.

The polarization beam splitting rotator is used for dividing an input optical signal into a path of optical signal with a horizontal polarization state and a path of optical signal with a vertical polarization state, and converting the optical signal with the vertical polarization state into the optical signal with the horizontal polarization state through rotation. Each optical phase shifting element 102 includes two optical phase shifters connected in parallel, and an input end and an output end of each optical phase shifter are an input end and an output end of the corresponding optical phase shifting element. That is, the optical phase shifting assembly includes upper and lower arms, each arm corresponds to an optical phase shifter, the upper arm and the lower arm form two waveguide branches, if the upper arm and the lower arm are completely symmetrical, when no control signal is applied, no phase difference exists between optical signals passing through the two waveguide branches, and if one or both arms simultaneously apply the control signal, the refractive index of the waveguide branches is changed, so that the phase difference of the optical signals output by the two arms is changed.

The optical phase shifting component can be driven by a single electrode or two electrodes. When the single electrode driving is adopted, a control voltage is applied to one arm of the optical phase shifting assembly, and the control voltage is not applied to the other arm, so that the phase difference of the output optical signals of the two arms is caused to change. When two electrodes are used for driving, two driving electric signals respectively applied to the two arms are different, for example, two driving electric signals with the same amplitude and opposite phases applied to the two arms respectively control the polarization states of the optical signals to generate opposite phase changes, so that the phase difference of the optical signals output by the two arms is caused to be changed. The two electrode drive scheme is also referred to as push-pull drive, and can achieve a halving of the amplitude of the applied electrical signal relative to the single electrode drive scheme.

The coupler is used for dividing the optical signals received by the two input ends into two paths of optical signal outputs after coupling, and is also called as a power divider. The coupler may be, for example, a multimode interference (multi-mode interferometer, MMI) coupler, among others.

Based on the polarization controller shown in fig. 1, an optical signal coupled to the polarization controller is first divided into two paths of optical signals in a horizontal polarization state by the polarization beam splitting rotator, and an input optical signal in any polarization state can be output into a specified polarization state, such as a horizontal polarization state, after passing through the polarization controller by adjusting the phase shift amount between two optical phase shifters in each optical phase shifting assembly. If the optical signal of the non-horizontal polarization state needs to be output, the output of the last-stage coupler is connected with a polarization beam splitting rotator, so that the light of the horizontal polarization state of the lower arm can be rotated back to the original vertical polarization state, and the optical signals of the upper arm and the lower arm are coupled into the optical signal of the single polarization state to be output. This process can also be accomplished by adjusting the amount of phase shift between the optical signals passing through the two optical phase shifters of each optical phase shifting assembly.

Wherein the adjustment of the amount of phase shift between the optical signals of the two optical phase shifters of each optical phase shifting assembly may be achieved by an electrical signal applied to the optical phase shifting assembly, which electrical signal may be, for example, a control voltage or a control current. Wherein the electrical signal selection control voltage or control current depends on the material of the optical phase shifter and is not illustrated here.

It should be noted that the number of optical phase shifting components and couplers in the polarization controller shown in fig. 1 is for illustration. Alternatively, the polarization controller may include more optical phase shifting components and couplers, which are not limited by the embodiments of the present application.

Based on the structure shown in fig. 1, it can be seen that the optical signal of random polarization coupled to the polarization controller becomes an optical signal of target polarization after rotation by the polarization controller. The target polarization state can be, for example, a horizontal polarization state, so that the optical signal output by the polarization controller can be coupled to the silicon-based optical chip for efficient transmission.

Fig. 2 is a schematic diagram of a system architecture of an optical communication network according to an embodiment of the present application. As shown in fig. 2, the optical communication network comprises a first network element 201 and a second network element 202. The first network element 201 is configured with a first optical module 2011, and the second network element 202 is configured with a second optical module 2021. The first optical module 2011 includes a first receiver and a first transmitter, and the second optical module 2022 includes a second receiver and a second transmitter.

As shown in fig. 2, a first optical transmission device 203 is connected between the first transmitter and the second receiver, and an optical signal transmitted by the first transmitter may be transmitted to the second receiver through the first optical transmission device 203. A second optical transmission device 204 is also connected between the second transmitter and the first receiver, and an optical signal transmitted by the second transmitter can be transmitted to the first receiver through the second optical transmission device 204.

The first transmitter modulates traffic data, which the first network element 201 needs to send to the second network element 202, onto an optical signal, and sends the modulated optical signal to the second receiver through the first optical transmission device 203. The second receiver demodulates the optical signal when receiving the optical signal to obtain service data, thereby completing transmission of the service data from the first network element 201 to the second network element 202.

The transmission procedure of service data between the second transmitter and the first receiver may refer to the transmission procedure of data between the first transmitter and the second receiver, and will not be described herein.

Wherein the first optical transmission means 203 and the second optical transmission means 204 in fig. 2 may be optical fibers, for example. In the scenario where the first optical transmission device 203 and the second optical transmission device 204 are optical fibers, the first optical transmission device 203 and the second optical transmission device 204 may multiplex the same optical fiber, or may use different optical fibers, which is not limited in the embodiment of the present application.

For the network architecture shown in fig. 2, if the receiver in the optical module is implemented by using a silicon-based integrated chip, the receiver is relatively sensitive to the polarization state of the received optical signal, so that the polarization controller shown in fig. 1 needs to be used to convert the input optical signal with any polarization state into the output optical signal with a fixed polarization state before inputting the optical signal to the receiver, and then the output optical signal with the fixed polarization state is coupled into the receiver, so that the receiver correctly demodulates the optical signal.

That is, the polarization controller shown in fig. 1 is applied to the data receiving side of the network shown in fig. 2. It should be noted that, as the on-chip integration technology matures, the polarization controller can be easily implemented on an integrated chip. Based on this, the polarization controller shown in fig. 1 can be integrated in the receiver of the optical module shown in fig. 2, and the integrated optical module has the advantages of small volume, low power consumption, small insertion loss and the like. Alternatively, the polarization controller shown in fig. 1 may be configured at the front end of the receiver separately from the receiver, which is not limited by the embodiment of the present application.

In addition, the first network element 201 and the second network element 202 may be data forwarding devices such as a switch, and the first optical module 2011 may be a single board chip inserted into the first network element 201, or may be a chip integrated into the first network element 201, which is not limited in the embodiment of the present application.

It should be noted that fig. 2 is an alternative application scenario of the polarization controller. The control method of the polarization controller provided by the embodiment of the application can also be applied to other scenes sensitive to the polarization state. Such as the input of a silicon-based optical switching chip, the receiving of a polarization multiplexing system, etc. For any scene, if the input optical signal is transmitted through the non-polarization-maintaining optical fiber in the scene, the polarization state of the transmitted optical signal is randomly rotated due to the non-polarization-maintaining optical fiber, so if the scene has specific requirements on the polarization state of the input optical signal, the input optical signal with any polarization state needs to be converted into the output optical signal with a fixed polarization state through the polarization controller.

In the process of resetting the control voltage of the optical phase shifter in the related art, since the polarization state of the optical signal is suddenly changed due to the resetting of the control voltage, service data in the optical communication network can be suspended to be transmitted during the resetting of the control voltage, so that the transmission efficiency of the service data can be affected. In addition, since the change of the SOP in the actual optical fiber transmission is random, when the optical fiber is subjected to severe vibration of the external environment such as passing by a train beside the optical fiber, or the ionization effect of lightning causes the change of the SOP to be very rapid, a method for rapidly realizing electrodeless control of the polarization controller is needed. I.e. the control voltage of the optical phase shifting component in the polarization controller reaches the boundary, the polarization state of the output optical signal of the polarization controller can be kept stable while the control voltage is reset rapidly. Based on the above, the embodiment of the application provides a control method of a polarization controller.

The following explains a control method of the polarization controller provided in the embodiment of the present application.

Fig. 3 is a flowchart of a control method of a polarization controller according to an embodiment of the present application. As shown in fig. 3, the method comprises the following steps 301 and 302.

Step 301: an initial adjustment amount of a control parameter of the first optical phase shifting assembly is determined based on a target polarization state of the optical signal, the control parameter being used to control an amount of phase shift of the optical signal passing through the respective optical phase shifting assembly.

For convenience of description, the optical signal output by the polarization controller is referred to as a first optical signal, and the polarization state to be achieved by the first optical signal is referred to as a target polarization state. In addition, the phase shift amount related to the embodiment of the application is the phase difference between the horizontal polarization state component and the vertical polarization state component of the optical signal.

Step 302: and if the sum of the current value of the control parameter of the first optical phase shifting component and the initial adjustment quantity exceeds the first boundary of the first allowable value interval, adjusting the values of the control parameters of the first optical phase shifting component and the second optical phase shifting component.

The second optical phase shifting component is an optical phase shifting component except the first optical phase shifting component in the N optical phase shifting components. In step 302, the values of the control parameters of the first optical phase shifting element and the second optical phase shifting element are adjusted to satisfy the following conditions:

The value of the control parameter of the first optical phase shifting component after adjustment is located in a first allowable value interval, the absolute value of the difference value between the first optical phase shifting component and the first boundary exceeds the absolute value of the initial adjustment quantity, and the polarization state of the optical signal passing through the polarization controller after adjustment is identical to the polarization state corresponding to the initial adjustment quantity, or the polarization state of the optical signal passing through the polarization controller before and after adjustment is unchanged.

The polarization state corresponding to the initial adjustment amount can be understood as: the control parameters of the first optical phase shifting element are assumed to be adjusted according to the initial adjustment amount, and the assumption is that the polarization state of the optical signal output by the polarization controller in the scene, that is, the polarization state originally expected to be achieved by the initial adjustment amount, may be simply referred to as the original expected polarization state in the following. In other words, the polarization state of the first optical signal after adjusting the control parameters of the second optical phase shifting element and the first optical phase shifting element reaches the original desired polarization state, or is the same as the polarization state of the first optical signal before adjusting the control parameters of the second optical phase shifting element and the first optical phase shifting element.

The following technical effects can be achieved through step 301 and step 302:

The value of the control parameter of the first optical phase shifting component after adjustment is positioned in the first allowable value interval, and the absolute value of the difference value between the first optical phase shifting component and the first boundary exceeds the absolute value of the initial adjustment quantity, so that the value of the control parameter of the first optical phase shifting component after adjustment can meet the condition required by the next adjustment. In this way, the adjustment of the control parameters of the first optical phase shifting element in step 302 corresponds to the resetting of the control parameters of the first optical phase shifting element.

(2) Ensuring that the polarization state of the output optical signal is unchanged or reaches the original expected polarization state in the resetting process

The polarization state of the first optical signal after adjusting the control parameters of the second optical phase shifting element and the first optical phase shifting element may be the same as the polarization state of the first optical signal before adjusting the control parameters of the second optical phase shifting element and the first optical phase shifting element. Thus, the polarization state of the optical signal output by the polarization controller is unchanged when the first optical phase shifting component and the second optical phase shifting component are adjusted by step 302.

And the polarization state of the first optical signal after the control parameters of the second optical phase shifting component and the first optical phase shifting component are adjusted can be the same as the polarization state corresponding to the initial polarization amount. Thus, when the first optical phase shifting element and the second optical phase shifting element are adjusted in step 302, the polarization state of the optical signal output by the polarization controller may reach the original desired polarization state as fast as the boundary.

Therefore, the step 302 can realize that the polarization state of the optical signal is unchanged or reaches the original expected polarization state in the process of resetting the first optical phase shifting component, so as to avoid abrupt change of the polarization state of the optical signal in the process of resetting.

In summary, in the embodiment of the present application, by adjusting the control parameters of the first optical phase shifting element and the second optical phase shifting element simultaneously, on the one hand, the resetting of the control parameters of the first optical phase shifting element can be completed. On the other hand, when the control parameter of the first optical phase shift is reset, the polarization states of the first optical signals before and after the reset are unchanged or reach the original expected polarization state, so that the abrupt change of the polarization states of the optical signals in the resetting process is avoided. Because the polarization state of the optical signal is not suddenly changed in the process of resetting the control parameters of the optical phase shifting assembly, the transmission of service data is not required to be interrupted when the control parameters of the optical phase shifting assembly are reset through the control method, and accordingly the transmission efficiency of the service data can be improved.

In some embodiments, for the polarization controller shown in fig. 1, rotating an optical signal of any polarization state to a target polarization state may be accomplished by a final three-stage optical phase shifting assembly in series in the polarization controller. In this scenario, the polarization controller shown in fig. 1 includes at least 4 couplers, one coupler is connected between each adjacent two of the N-2 th to N-th optical phase shift assemblies in the N optical phase shift assemblies, one coupler is connected to the input end of the N-2 th optical phase shift assembly, one coupler is connected to the output end of the N optical phase shift assembly, and the coupler connected to the output end of the N optical phase shift assembly is used for outputting the first optical signal.

At this time, the first optical phase shift element is one of the N-2 th to N-th optical phase shift elements, and the second optical phase shift element is one of the N-2 th to N-th optical phase shift elements other than the first optical phase shift element.

Further, when N is 3, the structure of the polarization controller shown in fig. 1 may be simplified to the polarization controller shown in fig. 4. In this scenario, the first optical phase shift element is one of the first-stage optical phase shift element to the third-stage optical phase shift element, and the second optical phase shift element is an optical phase shift element other than the first optical phase shift element of the first-stage optical phase shift element to the third-stage optical phase shift element.

In fig. 4, for convenience of description, the phase shift amount corresponding to the control parameter of the first-stage optical phase shift component is denoted as θ ₂ Marking the phase shift quantity corresponding to the control parameter of the second-stage optical phase shift component as phi ₁ Marking the phase shift quantity corresponding to the control parameter of the third-stage optical phase shift component as theta ₁ 。

For any optical phase shifting component, the phase shift amount corresponding to the control parameter of the optical phase shifting component can be understood as: when the control parameter of the optical phase shifting element is set to a certain value, the phase difference between the horizontal polarization state component and the vertical polarization state component of the optical signal passing through the optical phase shifting element.

For convenience of the following description, the specific manner of adjusting the second optical phase shifting element and the first optical phase shifting element in step 302 will be referred to as a target adjustment manner. Based on the polarization controllers shown in fig. 1 and 4, the target adjustment method may be exemplified by the following two methods.

(1) First target adjustment mode

When the first optical phase shift assembly is an nth stage optical phase shift assembly and the second optical phase shift assembly is an N-1 th stage optical phase shift assembly, the first target adjustment mode includes: adjusting control parameters of the N-1 level optical phase shifting component according to a first step length, wherein the phase shifting variable quantity corresponding to the first step length is kpi/2, and k is an odd number; and adjusting the control parameter of the first optical phase shifting component according to the target adjustment quantity, wherein the absolute value of the target adjustment quantity is the same as the absolute value of the initial adjustment quantity, and the direction of the target adjustment quantity is opposite to the direction of the initial adjustment quantity.

In the adjustment mode, the polarization state of the optical signal which passes through the polarization controller after adjustment is the same as the polarization state corresponding to the initial adjustment amount.

That is, for the polarization controller shown in fig. 1, if the current value of the control parameter of the nth stage optical phase shifting component is fast to the boundary of the first allowable value interval, the phase shift amount corresponding to the control parameter of the nth-1 stage optical phase shifting component is adjusted by an odd multiple of pi/2, and then the control parameter of the nth stage optical phase shifting component is adjusted in the opposite direction to the initial adjustment amount according to the magnitude of the initial adjustment amount.

For example, when n=3, the first target adjustment mode can be understood as: for the third-stage optical phase shift component in the polarization controller shown in fig. 4, when the control voltage of the third-stage optical phase shift component reaches any boundary, for example, the phase shift amount θ corresponding to the control voltage ₁ When the phase of the second-stage optical phase shift component is in the range of = ±pi, the control voltage of the second-stage optical phase shift component is changed to enable the phase shift quantity phi corresponding to the control voltage of the second-stage optical phase shift component ₁ Rotating by + -pi/2 (positive and negative can be selected), and adjusting the control voltage of the third-stage optical phase shift assembly according to the initial adjustment amount and in the opposite direction of the initial adjustment amount, thereby realizing the reset of the third-stage optical phase shift assembly and ensuring that the output polarization state is the same as the polarization state corresponding to the initial adjustment amount.

(2) Second target adjustment mode

In the case that the first optical phase shift assembly is an N-1 th stage optical phase shift assembly, and the second optical phase shift assembly includes an N-th stage optical phase shift assembly and an N-2 nd stage optical phase shift assembly, the second target adjustment mode includes: and adjusting the control parameter of the N-level optical phase shifting assembly from the first value to the second value, and adjusting the control parameter of the N-2-level optical phase shifting assembly from the third value to the fourth value, wherein the difference between the phase shift amount corresponding to the first value and the phase shift amount corresponding to the second value is the same as the difference between the phase shift amount corresponding to the third value and the phase shift amount corresponding to the fourth value. And adjusting the value of the control parameter of the first optical phase shifting component to a target value, wherein the target value is a numerical value in a target interval, the target interval is an interval in a first allowable value interval, and the absolute value of the difference value between the value in the target interval and the first boundary exceeds the absolute value of the initial adjustment quantity.

The adjusting the value of the control parameter of the first optical phase shifting component to the target value can be understood as: and adjusting the value of the control parameter of the first optical phase shifting component to any value far away from the first boundary.

That is, the second target adjustment mode can be understood as: for the polarization controller shown in fig. 1, if the current value of the control parameter of the N-1-th stage optical phase shifting component is as fast as any boundary of the allowed value interval, the phase shift amounts corresponding to the adjustment amounts of the N-th stage optical phase shifting component and the N-2-th stage optical phase shifting component are the same by adjusting the control parameters of the N-th stage optical phase shifting component and the N-2-th stage optical phase shifting component at the same time, and then the value of the control parameter of the N-1-th stage optical phase shifting component is adjusted to any value far from the first boundary.

In the second target adjustment mode, the phase shift amount corresponding to the second value of the Nth optical shift component is j pi, and j is an integer, and the value of the adjusted Nth optical shift component is not beyond the corresponding allowable value interval by controlling j because j is any integer, so that the value of the adjusted Nth optical shift component is not beyond the corresponding allowable value interval.

Further, in order to avoid that the control parameter of the N-1-th optical phase shift element is close to the second boundary of the first allowable value interval when the control parameter of the N-1-th optical phase shift element is adjusted next time, the control parameter of the N-1-th optical phase shift element is further away from the second boundary as far as possible when the control parameter of the N-1-th optical phase shift element is adjusted to any value away from the first boundary. The second boundary is another boundary except the first boundary in the first allowable value interval.

Therefore, the absolute value of the difference between the determined target value and the second boundary exceeds the absolute value of the initial adjustment amount, so that the target interval is far away from the first boundary and the second boundary.

For example, when n=3, the second target adjustment mode can be understood as: for the second-stage optical phase shifting component in the polarization controller shown in fig. 4, when the control voltage of the second-stage optical phase shifting component reaches any boundary, for example, the phase shift amount phi corresponding to the control voltage ₁ When the phase shift device is in the state of the = ±pi, the control voltages of the first-stage optical phase shift component and the third-stage optical phase shift component are simultaneously adjusted, the phase shift quantity corresponding to the control voltage adjustment quantity of the first-stage phase shifter is always consistent with the phase shift quantity corresponding to the control voltage adjustment quantity of the third-stage phase shifter in the adjustment process, and adjusting the value of the control voltage of the third-stage optical phase shifting component to a value when the corresponding phase shift amount is j pi, wherein j is an integer, such as 0. At this time, the control voltage of the second-stage optical phase shifting component is adjusted to be far away from two boundaries of the control voltage, so that the second-stage optical phase shifting component is reset, and the polarization state of the output light in the resetting process is ensured to be unchanged.

For ease of understanding, the rationality of the two target adjustment modes described above will be explained below using the polarization controller shown in fig. 4 as an example.

For the polarization controller shown in fig. 4, the transfer functions of a single coupler and a single optical phase shifting component can be expressed as follows:

the equivalent transfer function of the polarization controller shown in fig. 4 can be expressed as follows:

the electrodeless control of the polarization controller ensures that the polarization state of the output optical signal is basically unchanged when the control parameters of each level of optical phase shifting assembly are reset to the boundary in the adjustment process. Based on this, the following sets of expressions can be deduced:

E(kπ,φ ₁ +x,θ ₂ )＝e ^jx E(kπ,φ ₁ ,θ ₂ ) (10)

where E represents the polarization state of the optical signal output at the corresponding phase shift amounts of the three optical phase shift assemblies shown in fig. 4. Equation (10) shows the amount of phase shift θ corresponding to the control voltage of the third stage optical phase shifting element ₁ When the phase is not k pi, the phase shift quantity phi corresponding to the control voltage of the second-stage optical phase shift component ₁ Any phase can be rotated to ensure that the polarization state is unchanged.

E(θ ₁ +x,φ ₁ ±π/2,θ ₂ )＝±jE(θ ₁ -x,φ ₁ ,θ ₂ ) (11)

E(θ ₁ -x,φ ₁ ±π/2,θ ₂ )＝±jE(-θ ₁ +x,φ ₁ ,θ ₂ ) (12)

Equation (11-12) shows the phase shift amount θ corresponding to the control voltage of the third-stage optical phase shift element ₁ To the limit of e.g. theta ₁ When = ±pi; at this time, the phase shift amount phi corresponding to the control voltage of the second-stage optical phase shift component ₁ Can rotate any phase to let phi ₁ Rotation + -pi/2, at this time, the phase shift amount corresponding to the control voltage of the third-stage optical phase shift component is theta ₁ +x is equivalent to θ ₁ X, i.e. for the first toThe polarization state of the optical signal output by the polarization controller is unchanged under the two conditions of adjustment x and adjustment-x of the phase shift quantity corresponding to the control voltage of the three-stage optical phase shift assembly. Based on this, the first target adjustment mode is obtained.

E(θ ₁ +x,±π,θ ₂ +x)＝E(θ ₁ ,±π,θ ₂ ) (13)

Equation (13) shows that the control voltage of the second-stage optical phase shifting element corresponds to the phase shift amount phi ₁ To the limit of e.g. phi ₁ When the phase is in the range of plus or minus pi, the phase shift quantity theta corresponding to the control voltage of the third-stage optical phase shifting component is regulated ₁ Phase shift amount θ corresponding to control voltage of first-stage optical phase shift component ₂ So long as it ensures theta ₁ And theta ₂ The adjustment amount is consistent, and the polarization state output by the polarization controller is unchanged. Based on this, the second target adjustment mode described above can be obtained.

In addition, as can be seen from the above formula (10), the phase shift amount θ corresponding to the control voltage of the third-stage optical phase shift element ₁ When the phase is not k pi, the phase shift quantity phi corresponding to the control voltage of the second-stage optical phase shift component ₁ Any phase can be rotated to ensure that the polarization state is unchanged. Therefore, in the second target adjustment mode, the phase shift amount corresponding to the control voltage of the third-stage optical phase shift component can be further adjusted to be j pi, where j is an integer, so as to avoid that the adjusted control voltage of the first-stage optical phase shift component exceeds the corresponding allowable value interval.

Based on the above explanation of equation (10-13), an alternative adjustment in the reset process can be derived as follows:

(1) Resetting the third stage optical phase shifting assembly in the polarization controller of fig. 4 based on the first target adjustment: when the control voltage of the third-stage optical phase shifting component reaches the boundary, such as the corresponding phase shift amount theta ₁ When the phase is in the range of = ±pi, the control voltage of the second-stage optical phase shifting component is changed to enable the corresponding phase shifting quantity phi ₁ Rotating + -pi/2, adjusting the control voltage of the third-stage optical phase shifting component in the opposite direction of the initial adjustment amount, wherein the adjustment amount is the same as the initial adjustment amount, thereby realizing the reset of the third-stage optical phase shifting component and ensuring that the output polarization state reaches the original expectedPolarization state.

(2) Resetting the second-stage optical phase shifting component in the polarization controller of fig. 4 based on the second target adjustment mode: when the control voltage of the second-stage optical phase shifting component reaches the boundary, such as the corresponding phase shift phi ₁ When the phase shift value is = ±pi, the control voltages of the first-stage optical phase shift component and the third-stage phase shift component are simultaneously regulated, the phase shift value corresponding to the control voltage of the first-stage optical phase shift component is always consistent with the phase shift value corresponding to the control voltage of the third-stage optical phase shift component, and the phase shift value theta corresponding to the control voltage of the third-stage optical phase shift component is regulated ₁ J is an integer, such as 0. At this time, the control voltage of the second-stage optical phase shifting component is adjusted to be far away from the boundary of the control voltage, so that the resetting of the second-stage optical phase shifting component is realized, and the polarization state of the output light in the resetting process is ensured to be unchanged.

For ease of understanding, the derivation process of the above formula (10-13) is explained below:

for the polarization controller shown in fig. 4, an optical signal of arbitrary polarization state is inputAfter passing the polarization controller is horizontal polarized light +.>This process can be expressed by way of jones vectors as: />

The inverse matrix of the jones matrix is the conjugate transpose of the inverse matrix of the matrix of each stage multiplied by the two sides of the matrix, so that the method comprises the following steps:

equation (9-2) shows that horizontally polarized light is incident in the opposite direction through the polarization controller and can be changed into an optical signal of an arbitrary polarization state.

Electrodeless control of a polarization controller can be understood as: the output polarization state can be basically unchanged from the phase shift amount corresponding to the control parameter of each optical phase shift component in the formula (9-2) to the boundary, namely, the output polarization state can be basically unchanged from the value of the control parameter of each optical phase shift component to the boundary.

1. When the control parameter of the third-stage optical phase shifting component reaches the boundary, the phase shift quantity theta corresponding to the control parameter of the third-stage optical phase shifting component ₁ =kpi, equation (9-2) can be converted into the following equation (9-3):

based on the formula (9-3), assuming that the phase shift amount corresponding to the control parameter of the second-stage optical phase shift element is adjusted by x, the following formula (9-4) can be obtained:

2. if the phase shift quantity theta corresponding to the control parameter of the third-stage optical phase shift component ₁ To the limit of e.g. theta ₁ When the phase is close to k pi, let the control parameter of the second-stage optical phase shift component correspond to the phase shift phi ₁ Rotation +pi/2, for formula (9-2), there is:

because of theta ₁ Near =kpi, sin θ ₁ As an odd function, there is sin (θ ₁ +x)＝-sin(θ ₁ -x); and because of theta ₁ Near =kpi, cos θ ₁ As an even function, there is cos (θ ₁ +x)＝cos(θ ₁ -x); thus (9-5) can be converted into the following formula (9-6):

if the phase shift quantity theta corresponding to the control parameter of the third-stage optical phase shift component ₁ To the limit of e.g. theta ₁ When the phase is close to k pi, let the control parameter of the second-stage optical phase shift component correspond to the phase shift phi ₁ Rotation-pi/2, for formula (9-2)

Because of theta ₁ Near =kpi, sin θ ₁ As an odd function, there is sin (θ ₁ +x)＝-sin(θ ₁ -x); and because of theta ₁ Near =kpi, cos θ ₁ As an even function, there is cos (θ ₁ +x)＝cos(θ ₁ -x); thus (9-7) can be converted into the following formula (9-8):

the foregoing formula (11) can be obtained based on the formulas (9-6) and (9-8). The derivation of equation (12) is substantially the same as the derivation of equation (11), and will not be described in detail here.

3. If the phase shift amount phi corresponding to the control parameter of the second-stage optical phase shift assembly ₁ To the limit of e.g. phi ₁ When = ±pi, the formula (9-2) is:

the foregoing equation (13) can be obtained based on the equation (9-9): e (θ) ₁ +x,±π,θ ₂ +x)＝E(θ ₁ ,±π,θ ₂ )。

The first target adjustment method and the second target adjustment method are two exemplary target adjustment methods of the polarization controller shown in fig. 4. The target adjustment modes provided by the embodiment of the application are not limited to the two types, and any target adjustment mode capable of resetting the control parameters of the first optical phase shift assembly and simultaneously ensuring that the polarization state of the optical signal output by the polarization controller is not changed or reaches the original expected polarization state is within the scope of the embodiment of the application.

The first target adjustment method and the second target adjustment method are described by taking the polarization controller shown in fig. 4 as an example. Alternatively, when the polarization controller is a polarization controller with other structures, the corresponding target adjustment manner may be obtained based on the above-mentioned derivation process, and embodiments of the present application are not illustrated herein.

In addition, in any of the above target adjustment modes, the adjusted value of the control parameter of the second optical phase shift element is located in a second allowable value interval, and the second allowable value interval is an allowable value interval corresponding to the control parameter of the second optical phase shift element. That is, in the process of adjusting the control parameters of the first optical phase shift assembly and the second optical phase shift assembly at the same time, the adjustment of the control parameters of the second optical phase shift assembly to the boundary is avoided as much as possible, and the second optical phase shift assembly is required to be reset for further initiation.

Optionally, if the adjusted control parameter of the second optical phase shifting component exceeds any boundary of the second allowable value interval, resetting the control parameter of the second optical phase shifting component by adopting one of the target adjustment modes. For example, for the polarization controller shown in fig. 4, if the control parameter of the third-stage optical phase shifting component is required to be reset currently, the control parameter of the third-stage optical phase shifting component is reset based on the first target adjustment mode, and if the value of the control parameter of the second-stage optical phase shifting component is adjusted to exceed the boundary of the second allowable value interval in the resetting process based on the first target adjustment mode, the second-stage optical phase shifting component is used as the first optical phase shifting component to be reset, and the second-stage optical phase shifting component is reset based on the second target adjustment mode.

Furthermore, in an embodiment of the present application, the determining the initial adjustment amount of the first optical phase shifting element in step 301 may have the following two alternative implementations.

The first implementation mode: adaptive control algorithm

In the case of a target polarization state being a horizontal polarization state, a small portion of the light may be split at the output of the polarization controller and sent to a photodetector (photoelectric detector, PD) for optical power monitoring in order to make the polarization state of the output first optical signal be a horizontal polarization state. When the photodetector detects that the optical power of the vertical optical signal in the first optical signal is minimum, the horizontal polarization state of the first optical signal reaching the target is represented.

The vertical optical signal refers to a component optical signal with a polarization state being vertical polarization state among optical signals input to the polarization controller. For the polarization controller shown in fig. 1 or fig. 4, a vertical optical signal may be understood as an optical signal having a polarization state of vertical polarization obtained before rotation after PSR splitting. The two paths of optical signals after the PSR beam splitting may also be referred to as a TE optical signal and a TM optical signal, where the TE optical signal is a horizontal polarized optical signal, and the TM optical signal is a vertical polarized optical signal, and after the PSR beam splitting, the TM optical signal is also rotated into the TE optical signal, so that the TE optical signal is processed later, and an optical signal with a polarization state being a target polarization state is obtained. The target polarization state being a horizontal polarization state can be understood as: the power of TE optical signal after TM optical signal rotation in the optical signal output by the polarization controller is basically 0 after the subsequent optical phase shift component and coupler processing.

The power detected by the photodetector may be referred to as a PD output result, and the photodetector feeds back the PD output result to the control system, which implements closed loop feedback control of the entire polarization controller.

For the polarization controller shown in fig. 4, the basic principle of the adaptive control algorithm is: in order to lock the polarization state of the output optical signal of the polarization controller at the target polarization state, the control voltages of the second-stage optical phase shifting component and the third-stage optical phase shifting component are adaptively adjusted according to the PD output result. For example, the control voltages of the second-stage phase shifter and the third-stage phase shifter are adaptively adjusted by using a gradient algorithm.

Specifically, the control voltage of the second-stage phase shifter is adaptively adjusted. Detecting a current PD output result V1, if the power in the PD output result is detected to be larger, adjusting the control voltage (marked as V phi 1) of the second-stage phase shifter, firstly, trying to add a slight jitter delta V phi 1 to the control voltage of the current second-stage optical phase shifting component, then detecting a PD output result V2 after adding the jitter, if V2 is larger than V1, adjusting the control voltage V phi 1 of the second-stage optical phase shifting component according to the direction opposite to the jitter delta V phi 1, otherwise, if V2 is smaller than V1, adjusting the control voltage V phi 1 of the second-stage optical phase shifting component according to the direction same as the jitter delta V phi 1. The adjustment method of the control voltage (marked as V theta 1) of the third-stage optical phase shift component is consistent with the adjustment mode of the control voltage of the second-stage phase shifter.

The ΔVφ1 described above is a pre-configured fixed step size, which may be, for example, 0.1V.

In the process of adaptively adjusting the control parameter of any one of the optical phase shifting components, if the adjusted control parameter of the optical phase shifting component is within the corresponding allowable value interval before the PD output result reaches the minimum, the polarization state of the first optical signal is locked when the PD output result reaches the minimum. If the adjusted control parameter of the optical phase shift device is not within the corresponding allowable value interval during any adjustment, the control parameter of the optical phase shift device needs to be reset, and the resetting process refers to step 302.

Based on this, the implementation of step 301 may be: under the condition that the target polarization state is the horizontal polarization state, acquiring the power of a polarization state vertical optical signal in the first optical signal; if the power of the vertical optical signal in the first optical signal exceeds the power threshold value, determining an initial adjustment amount based on the first allowable value interval and the second step length.

The power threshold and the second step size are parameters configured in advance based on the performance of the polarization controller.

In addition, in the adaptive control algorithm, since it is necessary to acquire the power of the vertical optical signal from the optical signal output from the polarization controller, a photodetector may be further disposed in the polarization controller, and the photodetector is used to detect the aforementioned PD detection result.

That is, the polarization controller shown in fig. 1 or 4 further includes a photodetector connected to a port for outputting the first optical signal in the polarization controller. The photodetector is used for detecting the power of the optical signal with the polarization state being the vertical polarization state in the first optical signal.

The second implementation mode: analytical control algorithm

In the polarization controller shown in fig. 1 or 4, the polarization controller further includes a polarization measuring instrument connected to the input terminal of the N-1 st stage optical phase shifting assembly. The polarization measuring instrument is used for detecting Stokes vectors. In this case, from the output of the coupler connected to the input of the N-1 st stage optical phase shift element of the polarization controller, a part of the optical signal is sent to the polarization measuring instrument to perform stokes vector detection. Based on the detected Stokes vector, an equivalent Jones matrix J of the transmission process of the optical signal transmitted by the transmitter in the optical fiber, the first to N-2 th stages of optical phase shifters in the polarization controller, and the coupler connected to the output end of the N-2 th stage of optical phase shifter can be obtained _Tot 。

J _Tot Can be described as:

based on the jones matrix, the analytical control algorithm can be implemented in the following two steps.

The first step: the Stokes vector detected by the polarization measuring instrument is firstly used for obtaining the equivalent Jones matrixThe control parameters of the N-1 level optical phase shifting component of the polarization controller are then adjusted to make the phase shift amount generated by the N-1 level optical phase shifting component be +.>

And a second step of: stokes vectors detected by the polarization measuring instrument,obtaining delta theta in equivalent Jones matrix ₀ The control parameters of the N-stage optical phase shifting component of the polarization controller are then adjusted to make the phase shift amount generated by the N-stage optical phase shifting component be k pi-delta theta ₀ 。

In the two steps, if the values of the control parameters of the N-1 level optical phase shifting assembly and the N level optical phase shifting assembly after adjustment do not reach the boundary of the corresponding allowable value interval, the locking of the polarization state of the output first optical signal can be completed. However, if the adjusted control parameter of a certain optical phase shifting element reaches the boundary, the reset is performed on the control parameter of the optical phase shifting element, and the reset process refers to the step 302.

Based on this, in the case that the first optical phase shifting element is the N-1 th level optical phase shifting element or the N-th level optical phase shifting element, the implementation manner of determining the initial adjustment amount of the control parameter of the first optical phase shifting element based on the target polarization state in step 301 may be: acquiring Stokes vectors of optical signals output by an N-1-th stage coupler, wherein the N-1-th stage coupler is a coupler connected with the input end of an N-1-th stage optical phase shifting component; an initial adjustment of a control parameter of the first optical phase shifting component is determined based on the stokes vector and the target polarization state.

It should be noted that, in the analysis control algorithm, the first step and the second step are sequential, that is, the control parameters of the nth stage optical phase shift assembly need to be adjusted based on the first step, and then the control parameters of the N-1 th stage optical phase shift assembly need to be adjusted based on the second step.

In order to facilitate understanding of the embodiments of the present application, the basic principle of the analysis control algorithm will be explained below by taking the polarization controller shown in fig. 4 as an example.

Based on the polarization controller shown in fig. 4, the equivalent jones matrix J of the total transmission process of the optical signal transmitted by the transmitter in the optical fiber and the polarization controller _Tot Can be expressed as:

J _Tot ＝(15)

transmitterEquivalent Jones matrix J of transmission process of transmitted optical signal in optical fiber, first-stage optical phase shifting component of polarization controller and coupler connected with first-stage optical phase shifting component _Tot Can be expressed as:

obtained by a polarization measuring instrumentAdjusting the control parameters of the second-stage phase shifter so that the corresponding phase shift amount is +.>The above equation (16) can be converted into the following equation:

at this time, Δθ of the equivalent jones matrix is detected by the polarization measuring instrument ₀ The phase shift amount of the third-stage phase shifter of the polarization controller is adjusted to be k pi-delta theta ₀ The total transmission matrix can thus be given by:

The optical signal in horizontal polarization state sent by the transmitter can also be the optical signal in horizontal polarization state through the total transmission matrix.

The reset procedure in the two implementations is explained in detail below.

Fig. 5 is a schematic diagram of another control method of a polarization controller according to an embodiment of the present application, where the control method is implemented based on the adaptive control algorithm described above. The method shown in fig. 5 is applied to the polarization controller shown in fig. 6.

As shown in fig. 5 and fig. 6, an input optical signal with random polarization state is first divided into two paths of TE-mode light by a polarization beam splitting rotator, then is output by a cascaded four-stage MMI and three-stage optical phase shifting assembly, and if the optical signal output by a desired polarization controller is an optical signal with horizontal polarization state, the optical power of a vertical optical signal detected by the PD can be minimized by inputting a part of the optical signal output by the polarization controller to a Photodetector (PD) and adjusting the control voltage of each optical phase shifting assembly in the polarization controller by a control system.

For the polarization controller shown in fig. 6, as shown in fig. 5, the control voltages of the second-stage optical phase shift assembly and the third-stage optical phase shift assembly are adaptively adjusted according to the PD output result. The order of adjustment of the two is not particularly limited. For example, the control voltage of the second-stage optical phase shift assembly may be adjusted once after the control voltage of the second-stage optical phase shift assembly is adjusted once, and then the control voltage of the second-stage optical phase shift assembly is adjusted once again, so that the control voltages of the second-stage optical phase shift assembly and the third-stage optical phase shift assembly are alternately adjusted.

In the process of adjusting the control voltages of the second-stage optical phase shifting component and the third-stage optical phase shifting component, when the control voltage of the third-stage optical phase shifting component reaches a boundary, adjusting the control voltage of the second-stage optical phase shifting component, enabling the corresponding phase shift amount of the control voltage of the second-stage optical phase shifting component to rotate by +/-pi/2, adjusting the control voltage of the third-stage optical phase shifting component in the opposite direction of the initial adjustment amount, and adjusting the magnitude of the initial adjustment amount.

In the process of adjusting the control voltages of the second-stage optical phase shifting component and the third-stage optical phase shifting component, when the control voltage of the second-stage optical phase shifting component reaches the boundary, the control voltages of the first-stage optical phase shifting component and the third-stage phase shifting component are adjusted at the same time, the phase shift amount corresponding to the control voltage of the first-stage optical phase shifting component is always kept consistent with the phase shift amount corresponding to the control voltage of the third-stage optical phase shifting component, and the phase shift amount theta corresponding to the control voltage of the third-stage optical phase shifting component is adjusted ₁ J pi, j is an integer. At this time, the control voltage of the second-stage optical phase shifting component is adjusted to be far away from the boundary of the control voltage.

In summary, in the flow shown in fig. 5, the polarization controller architecture implemented with the three-stage optical phase shifting assembly implements conversion of an input optical signal of any polarization state into an output optical signal of a fixed polarization state. Such as the polarization state of the output optical signal being a horizontal polarization state. And according to PD output results, adaptively adjusting control voltages of the second-stage optical phase shifting component and the third-stage optical phase shifting component, so that the polarization state of the output optical signal is locked at a fixed polarization state for output. When the control voltages of the second-stage and third-stage optical phase shifting components of the polarization controller reach the boundary, the control voltages of the two-stage phase shifters are reset according to the two steps shown in fig. 5, and the polarization state of the output light in the resetting process can be ensured to be unchanged or maintained in the original expected polarization state, namely, the electrodeless control of the polarization controller is realized.

Fig. 7 is a schematic diagram of another control method of a polarization controller according to an embodiment of the present application, where the control method is implemented based on the above-mentioned analytical control algorithm. The method shown in fig. 7 is applied to the polarization controller shown in fig. 8.

As shown in fig. 7 and 8, the input optical signal with random polarization state is first divided into two paths of TE-mode light by the polarization beam splitting rotator, then output by the cascaded four-stage MMI and three-stage optical phase shifting assembly, and if the optical signal output by the desired polarization controller is an optical signal with horizontal polarization state, a part of the optical signal can be sent to the polarization measuring instrument for stokes vector detection from the output of the coupler connected with the input end of the N-1 stage optical phase shifting assembly of the polarization controller. The control system obtains a phase shift component for the N-1 th order light based on the detected Stokes vectorThe control parameters of the N-1 level optical phase shifting component are adjusted to enable the phase shifting quantity generated by the N-1 level optical phase shifting component to be +.>

The control system then derives Δθ for the nth order optical phase shifting component based on the detected stokes vector ₀ The control parameters of the N-stage optical phase shifting component are adjusted to ensure that the phase shifting quantity generated by the N-stage optical phase shifting component is k pi-delta theta ₀ 。

In the above-described process of adjusting the control voltages of the second-stage optical phase shift element and the third-stage optical phase shift element, when the control voltage of the second-stage optical phase shift element or the third-stage optical phase shift element reaches the boundary, the same resetting process as in the flow shown in fig. 7 is performed, and the description thereof will not be repeated.

Based on the control method of the polarization controller shown in fig. 5 and fig. 7, when any one stage of optical phase shifting component of the polarization controller is controlled, when the control voltage reaches a boundary, according to the working principle of the polarization controller deduced by theory, the control voltage of other optical phase shifting components is changed first, and then the optical phase shifting component reaching the boundary is adjusted, so that the control voltage is reset quickly, and the polarization state of an output optical signal is not changed or maintained to be the original expected polarization state. Compared with the method that the transmission of service data is interrupted when the polarization controller needs to be reset, the method provided by the embodiment of the application does not need to interrupt the transmission of the service data, and the resetting process has theoretical guidance, and the resetting of the optical phase shifting component can be realized in two steps, so that the embodiment of the application can be applied to the scene of the rapid change of the polarization state of an input optical signal.

In summary, when the control voltage of a certain level of optical phase shifting component of the polarization controller reaches a boundary, the method provided by the embodiment of the application adjusts the control voltages of other levels of optical phase shifting components according to a specific amount, so as to reset the control voltage of the optical phase shifting component reaching the boundary while ensuring that the polarization state of an output optical signal is unchanged or maintained at the original expected polarization state.

In addition, the embodiment of the application realizes the on-chip polarization controller through the multistage light phase shifting component and the coupler, can realize the electrodeless control of the polarization controller, and has simple hardware control. The control of the polarization controller can adopt a self-adaptive control algorithm or an analysis algorithm to adjust the control voltage of each level of optical phase shifting component, the resetting process is quick by adopting the method of the embodiment of the application, and the polarization state of the output optical signal can be ensured to be strictly unchanged or maintained in the original expected polarization state, so the embodiment of the application can be applied to the scene of the rapid change of the polarization state of the input optical signal.

Fig. 9 is a schematic structural diagram of a control device of a polarization controller according to an embodiment of the present application, which may be integrated in the control system shown in fig. 6 or fig. 8. As shown in fig. 9, the control device includes the following modules.

The determining module 901 is configured to determine, based on a target polarization state of the optical signal, an initial adjustment amount of a control parameter of the first optical phase shifting component, where the control parameter is used to control a phase shift amount of the optical signal passing through the corresponding optical phase shifting component, and the phase shift amount is a phase difference between a horizontal polarization state component and a vertical polarization state component of the optical signal. Specific implementations may refer to step 301 in the embodiment of fig. 3.

And the adjusting module 902 is configured to adjust the values of the control parameters of the first optical phase shifting element and the second optical phase shifting element if the sum of the current value of the control parameter of the first optical phase shifting element and the initial adjustment amount exceeds a first boundary of a first allowable value interval, so that the value of the control parameter of the first optical phase shifting element is located in the first allowable value interval and the absolute value of the difference value between the control parameter of the first optical phase shifting element and the first boundary exceeds the absolute value of the initial adjustment amount, and the polarization state of the optical signal after adjustment passing through the polarization controller is the same as the polarization state corresponding to the initial adjustment amount, or the polarization state of the optical signal before and after adjustment passing through the polarization controller is unchanged. Specific implementations may refer to step 302 in the embodiment of fig. 3.

The second optical phase shifting component is an optical phase shifting component except the first optical phase shifting component in the N optical phase shifting components.

Optionally, the polarization controller further includes 4 couplers, N optical phase shifting components are connected in series, one coupler is connected between each adjacent two of the N-2 th to N-th optical phase shifting components, the input end of the N-2 nd optical phase shifting component is connected with one coupler, the output end of the N-th optical phase shifting component is connected with one coupler, and the coupler connected with the output end of the N-th optical phase shifting component is used for outputting optical signals rotated by the polarization controller;

The first optical phase shifting component is one of an N-2-th optical phase shifting component and an N-th optical phase shifting component, and the second optical phase shifting component is an optical phase shifting component except the first optical phase shifting component in the N-2-th optical phase shifting component and the N-th optical phase shifting component.

Optionally, the first optical phase shifting component is an nth level optical phase shifting component, and the second optical phase shifting component is an nth-1 level optical phase shifting component;

the adjusting module is used for:

adjusting the value of a control parameter of the N-1 level optical phase shifting component according to a first step length, wherein the phase shifting variable quantity corresponding to the first step length is kpi/2, and k is an odd number;

adjusting the value of the control parameter of the Nth-stage optical phase shifting component according to the target adjustment quantity, wherein the absolute value of the target adjustment quantity is the same as that of the initial adjustment quantity, and the direction of the target adjustment quantity is opposite to that of the initial adjustment quantity;

the polarization state of the optical signal after adjustment passing through the polarization controller is the same as the polarization state corresponding to the initial adjustment amount.

Optionally, the first optical phase shifting component is an nth-1 optical phase shifting component, and the second optical phase shifting component comprises an nth optical phase shifting component and an nth-2 optical phase shifting component;

the adjusting module is used for:

adjusting the control parameter of the N-level optical phase shifting assembly from a first value to a second value, and adjusting the control parameter of the N-2-level optical phase shifting assembly from a third value to a fourth value, wherein the difference between the phase shift amount corresponding to the first value and the phase shift amount corresponding to the second value is the same as the difference between the phase shift amount corresponding to the third value and the phase shift amount corresponding to the fourth value;

Adjusting the value of the control parameter of the N-1 level optical phase shifting component to a target value, wherein the target value is a numerical value in a target interval, the target interval is positioned in the range of a first allowable value interval, and the absolute value of the difference value between any numerical value in the target interval and the first boundary exceeds the absolute value of the initial adjustment quantity;

wherein, the polarization state of the optical signal passing through the polarization controller before and after the adjustment is unchanged.

Optionally, the phase shift amount corresponding to the second value is jpi, and j is an integer.

Optionally, the absolute value of the difference between any one of the values in the target interval and the second boundary exceeds the absolute value of the initial adjustment amount, and the second boundary is another boundary in the first allowable value interval other than the first boundary.

Optionally, the adjusted value of the control parameter of the second optical phase shift component is located in a second allowed value interval, where the second allowed value interval is the allowed value interval corresponding to the control parameter of the second optical phase shift component.

Optionally, the first optical phase shifting component is an N-1 th level optical phase shifting component or an N-th level optical phase shifting component;

the determining module is used for:

acquiring Stokes vectors of optical signals output by an N-1-th stage coupler, wherein the N-1-th stage coupler is a coupler connected with the input end of an N-1-th stage optical phase shifting component;

An initial adjustment of a control parameter of the first optical phase shifting component is determined based on the stokes vector and the target polarization state.

Optionally, the polarization controller further comprises a polarization measuring instrument, and the polarization measuring instrument is connected with the input end of the N-1 level optical phase shifting component;

the polarization measuring instrument is used for detecting Stokes vectors.

Optionally, the determining module is configured to:

when the target polarization state is the horizontal polarization state, acquiring the power of a vertical optical signal in the optical signals output by the polarization controller, wherein the vertical optical signal refers to the vertical polarization state component of the optical signals input to the polarization controller;

if the power exceeds the power threshold, an initial adjustment amount is determined based on the first allowable value interval and the second step size.

Optionally, the polarization controller further comprises a photodetector, and the photodetector is connected with a port for outputting an optical signal in the polarization controller;

the photoelectric detector is used for detecting the power of the vertical optical signal in the optical signals output by the polarization controller.

When the control voltage of a certain level of optical phase shifting component of the polarization controller reaches the boundary, the embodiment of the application adjusts the control voltages of other levels of optical phase shifting components according to a specific quantity so as to reset the control voltage of the optical phase shifting component reaching the boundary while ensuring that the polarization state of an output optical signal is unchanged or maintained at the original expected polarization state.

It should be noted that: in the device provided in the above embodiment, when the polarization controller is controlled, only the division of the above functional modules is used for illustration, in practical application, the above functional allocation may be performed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules, so as to complete all or part of the functions described above. In addition, the apparatus provided in the foregoing embodiment belongs to the same concept as the foregoing control method embodiment, and specific implementation processes of the apparatus are detailed in the method embodiment, which is not described herein again.

Fig. 10 is a schematic structural diagram of a control system according to an embodiment of the present application, where the control system may be the control system shown in fig. 6 or fig. 8. Referring to fig. 10, the control system includes at least one processor 1001, a communication bus 1002, a memory 1003, and at least one communication interface 1004.

The processor 1001 may be a microprocessor (including a central processing unit (central processing unit, CPU), etc.), an application-specific integrated circuit (ASIC), or may be one or more integrated circuits for controlling the execution of programs in accordance with aspects of the present application.

Communication bus 1002 may include a path for communicating information between the components.

The memory 1003 may be, but is not limited to, read-Only memory (ROM), random-access memory (random access memory, RAM), electrically erasable programmable read-Only memory (electrically erasable programmable read-Only memory, EEPROM), optical disks (including compact disk (compact disc read-Only memory, CD-ROM), compact disk, laser disk, digital versatile disk, blu-ray disk, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and capable of being accessed by a computer. The memory 1003 may be separate and coupled to the processor 1001 by a communication bus 1002. Memory 1003 may also be integrated with processor 1001.

Wherein the memory 1003 is used for storing program code 1010 for executing the inventive arrangements, and the processor 1001 is used for executing the program code 1010 stored in the memory 1003. The computer device may implement the control method provided by the embodiment of fig. 3 by means of a processor 1001 and a program code 1010 in a memory 1003.

The communication interface 1004 uses any transceiver-like device for communicating with other devices or communication networks.

In a particular implementation, as one embodiment, the processor 1001 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 2.

In a particular implementation, as one embodiment, a computer device may include multiple processors, such as processor 1001 and processor 1005 shown in FIG. 2. Each of these processors may be a single-core processor or a multi-core processor. A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

The computer device may be a general purpose computer device or a special purpose computer device. In a specific implementation, the computer device may be a desktop, a portable computer, a network server, a palm computer, a mobile phone, a tablet computer, a wireless terminal device, a communication device, or an embedded device, and the embodiment of the application is not limited to the type of computer device.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, data subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., digital versatile Disk (Digital Versatile Disc, DVD)), or a semiconductor medium (e.g., solid State Disk (SSD)), etc.

The above embodiments are not intended to limit the present application, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. The control method of the polarization controller is characterized in that the polarization controller comprises N optical phase shifting components, and N is a positive integer greater than 1; the method comprises the following steps:

determining an initial adjustment amount of a control parameter of the first optical phase shift assembly based on a target polarization state of the optical signal, the control parameter being used to control a phase shift amount of the optical signal passing through the corresponding optical phase shift assembly, the phase shift amount being a phase difference between a horizontal polarization state component and a vertical polarization state component of the optical signal;

if the sum of the current value of the control parameter of the first optical phase shifting component and the initial adjustment quantity exceeds a first boundary of a first allowable value interval, adjusting the values of the control parameters of the first optical phase shifting component and the second optical phase shifting component so that the value of the control parameter of the first optical phase shifting component is positioned in the first allowable value interval, the absolute value of the difference value between the control parameter of the first optical phase shifting component and the first boundary exceeds the absolute value of the initial adjustment quantity, and the polarization state of the optical signal passing through the polarization controller after adjustment is the same as the polarization state corresponding to the initial adjustment quantity, or the polarization state of the optical signal passing through the polarization controller before and after adjustment is unchanged;

2. The method of claim 1, wherein the polarization controller further comprises 4 couplers, the N optical phase shifting components are connected in series, one coupler is connected between each adjacent two of the N-2 th to N-th optical phase shifting components, one coupler is connected to the input end of the N-2 th optical phase shifting component, one coupler is connected to the output end of the N-th optical phase shifting component, and the coupler connected to the output end of the N-th optical phase shifting component is used for outputting the optical signal rotated by the polarization controller;

the first optical phase shifting component is one of the N-2-stage optical phase shifting component and the N-stage optical phase shifting component, and the second optical phase shifting component is the optical phase shifting component except the first optical phase shifting component in the N-2-stage optical phase shifting component and the N-stage optical phase shifting component.

3. The method of claim 2, wherein the first optical phase shifting component is the nth order optical phase shifting component and the second optical phase shifting component is the N-1 th order optical phase shifting component;

The adjusting the values of the control parameters of the first optical phase shifting component and the second optical phase shifting component comprises the following steps:

adjusting the value of the control parameter of the N-1 level optical phase shifting component according to a first step length, wherein the phase shifting variable quantity corresponding to the first step length is kpi/2, and k is an odd number;

adjusting the value of the control parameter of the Nth-stage optical phase shifting component according to a target adjustment quantity, wherein the absolute value of the target adjustment quantity is the same as the absolute value of the initial adjustment quantity, and the direction of the target adjustment quantity is opposite to the direction of the initial adjustment quantity;

4. The method of claim 2, wherein the first optical phase shifting component is the N-1 th stage optical phase shifting component, and the second optical phase shifting component comprises the N-th stage optical phase shifting component and the N-2 th stage optical phase shifting component;

adjusting the control parameter of the Nth-level optical phase shifting component from a first value to a second value, and adjusting the control parameter of the N-2 th-level optical phase shifting component from a third value to a fourth value, wherein the difference between the phase shift amount corresponding to the first value and the phase shift amount corresponding to the second value is the same as the difference between the phase shift amount corresponding to the third value and the phase shift amount corresponding to the fourth value;

Adjusting the value of the control parameter of the N-1 level optical phase shifting component to a target value, wherein the target value is a numerical value in a target interval, the target interval is positioned in the range of the first allowable value interval, and the absolute value of the difference value between any numerical value in the target interval and the first boundary exceeds the absolute value of the initial adjustment quantity;

wherein, the polarization state of the optical signal passing through the polarization controller before and after adjustment is unchanged.

5. The method of claim 4, wherein the phase shift amount corresponding to the second value is j pi, where j is an integer.

6. The method of claim 4 or 5, wherein an absolute value of a difference between any one of the values in the target interval and a second boundary, which is another boundary in the first allowable value interval other than the first boundary, exceeds an absolute value of the initial adjustment amount.

7. The method of any of claims 3-6, wherein the adjusted value of the control parameter of the second optical phase shifting element is within a second allowable value interval, the second allowable value interval being an allowable value interval corresponding to the control parameter of the second optical phase shifting element.

8. The method of any of claims 2-7, wherein the first optical phase shifting component is the N-1 th stage optical phase shifting component or the N-th stage optical phase shifting component;

the determining an initial adjustment of a control parameter of the first optical phase shifting component based on a target polarization state of the optical signal includes:

acquiring a Stokes vector of an optical signal output by an N-1-th stage coupler, wherein the N-1-th stage coupler is a coupler connected with the input end of the N-1-th stage optical phase shifting component;

9. The method of claim 8, wherein the polarization controller further comprises a polarization meter, the polarization meter being coupled to an input of the N-1 stage optical phase shifting assembly;

the polarization measuring instrument is used for detecting the Stokes vector.

10. The method of any of claims 1-7, wherein determining an initial adjustment of a control parameter of the first optical phase shifting assembly based on a target polarization state of the optical signal comprises:

acquiring the power of a vertical optical signal in the optical signals output by the polarization controller under the condition that the target polarization state is a horizontal polarization state, wherein the vertical optical signal refers to a vertical polarization state component of the optical signals input to the polarization controller;

And if the power exceeds a power threshold, determining the initial adjustment amount based on the first allowable value interval and a second step length.

11. The method of claim 10, wherein the polarization controller further comprises a photodetector connected to a port in the polarization controller for outputting the optical signal;

the photoelectric detector is used for detecting the power of a vertical optical signal in the optical signals output by the polarization controller.

12. A control device of a polarization controller, wherein the polarization controller comprises N optical phase shifting components, N being a positive integer greater than 1; the device comprises:

a determining module, configured to determine, based on a target polarization state of an optical signal, an initial adjustment amount of a control parameter of a first optical phase shift assembly, where the control parameter is used to control a phase shift amount of the optical signal passing through a corresponding optical phase shift assembly, where the phase shift amount is a phase difference between a horizontal polarization state component and a vertical polarization state component of the optical signal;

the adjusting module is used for adjusting the values of the control parameters of the first optical phase shifting assembly and the second optical phase shifting assembly if the sum of the current value of the control parameters of the first optical phase shifting assembly and the initial adjustment quantity exceeds a first boundary of a first allowable value interval, so that the value of the control parameters of the first optical phase shifting assembly is positioned in the first allowable value interval, the absolute value of the difference value between the control parameters of the first optical phase shifting assembly and the first boundary exceeds the absolute value of the initial adjustment quantity, and the polarization state of an optical signal passing through the polarization controller after adjustment is the same as the polarization state corresponding to the initial adjustment quantity, or the polarization state of an optical signal passing through the polarization controller before and after adjustment is unchanged;

13. The apparatus of claim 12, wherein the polarization controller further comprises 4 couplers, the N optical phase shifting elements are connected in series, one coupler is connected between each adjacent two of the N-2 th to N-th optical phase shifting elements, one coupler is connected to the input end of the N-2 th optical phase shifting element, one coupler is connected to the output end of the N-th optical phase shifting element, and the coupler connected to the output end of the N-th optical phase shifting element is used for outputting the optical signal rotated by the polarization controller;

14. The apparatus of claim 13, wherein the first optical phase shifting component is the nth order optical phase shifting component and the second optical phase shifting component is the N-1 th order optical phase shifting component;

The adjusting module is used for:

15. The apparatus of claim 13, wherein the first optical phase shifting component is the N-1 th order optical phase shifting component, and the second optical phase shifting component comprises the N-th order optical phase shifting component and the N-2 th order optical phase shifting component;

the adjusting module is used for:

16. The apparatus of claim 15, wherein the second value corresponds to a phase shift of j pi, where j is an integer.

17. The apparatus of claim 15 or 16, wherein an absolute value of a difference between any one of the values in the target interval and a second boundary, the second boundary being another boundary of the first allowable value interval other than the first boundary, exceeds an absolute value of the initial adjustment amount.

18. The apparatus of any of claims 14-17, wherein the adjusted value of the control parameter of the second optical phase shifting element is within a second allowable value interval, the second allowable value interval being an allowable value interval corresponding to the control parameter of the second optical phase shifting element.

19. The apparatus of any of claims 13-18, wherein the first optical phase shifting element is the N-1 th order optical phase shifting element or the N-th order optical phase shifting element;

the determining module is used for:

20. The apparatus of claim 19, wherein the polarization controller further comprises a polarization meter, the polarization meter being coupled to an input of the N-1 stage optical phase shifting assembly;

the polarization measuring instrument is used for detecting the Stokes vector.

21. The apparatus of any one of claims 12-18, wherein the determining module is configured to:

22. The apparatus of claim 21, wherein the polarization controller further comprises a photodetector coupled to a port in the polarization controller for outputting the optical signal;

23. A control system, the control system comprising a processor and a memory:

the memory is used for storing a program required for executing the method of any one of claims 1 to 11;

the processor is configured to execute a program stored in the memory.

24. A computer readable storage medium having instructions stored therein which, when run on a computer, cause the computer to perform the method of any of claims 1-11.